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<head><meta charset="utf-8"><title>Filter out query machinery from compiler … compiler-team#410 · t-compiler/major changes · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/index.html">t-compiler/major changes</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html">Filter out query machinery from compiler … compiler-team#410</a></h3>

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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Filter%20out%20query%20machinery%20from%20compiler%20%E2%80%A6%20compiler-team%23410/near/228750078" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> triagebot <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html#228750078">(Mar 04 2021 at 10:43)</a>:</h4>
<p>A new proposal has been announced: <a href="https://github.com/rust-lang/compiler-team/issues/410">Filter out query machinery from compiler backtraces by default #410</a>. It will be announced at the next meeting to try and draw attention to it, but usually MCPs are not discussed during triage meetings. If you think this would benefit from discussion amongst the team, consider proposing a design meeting.</p>



<a name="228752581"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Filter%20out%20query%20machinery%20from%20compiler%20%E2%80%A6%20compiler-team%23410/near/228752581" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> RalfJ <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html#228752581">(Mar 04 2021 at 11:05)</a>:</h4>
<p>oO that proposd implementation sounds a lot like a built-in hacky version of <a href="https://github.com/dtolnay/linkme">https://github.com/dtolnay/linkme</a>, or am I misunderstanding? Cc <span class="user-mention" data-user-id="124288">@oli</span></p>



<a name="228753293"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Filter%20out%20query%20machinery%20from%20compiler%20%E2%80%A6%20compiler-team%23410/near/228753293" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> oli <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html#228753293">(Mar 04 2021 at 11:10)</a>:</h4>
<p>it's pretty much exactly that, except imo it's less hacky than the <code>linkme</code> crate, as it does not rely on linker functionality. It's the MVP needed for <a href="https://github.com/rust-lang/const-eval/issues/25#issuecomment-533840428">https://github.com/rust-lang/const-eval/issues/25#issuecomment-533840428</a> (which itself is desirable for custom test harnesses, tracing metadata and custom const-evaluated artifacts).</p>



<a name="228763623"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Filter%20out%20query%20machinery%20from%20compiler%20%E2%80%A6%20compiler-team%23410/near/228763623" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html#228763623">(Mar 04 2021 at 12:33)</a>:</h4>
<p>I'm a bit surprised by the lexical order claim - is this performance sensitive for some reason? Seems fine, just interested if my assumption is wrong that it shouldn't really be called often</p>



<a name="228763841"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Filter%20out%20query%20machinery%20from%20compiler%20%E2%80%A6%20compiler-team%23410/near/228763841" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> oli <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html#228763841">(Mar 04 2021 at 12:34)</a>:</h4>
<p>the list may get very big, I don't know. And we would have to walk it for every frame in the backtrace. But even so, I don't like having constants whose value depends on arbitrary decisions by the compiler</p>



<a name="228764106"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Filter%20out%20query%20machinery%20from%20compiler%20%E2%80%A6%20compiler-team%23410/near/228764106" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html#228764106">(Mar 04 2021 at 12:36)</a>:</h4>
<p>Sure, was just wondering.</p>



<a name="228767905"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Filter%20out%20query%20machinery%20from%20compiler%20%E2%80%A6%20compiler-team%23410/near/228767905" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> oli <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html#228767905">(Mar 04 2021 at 13:04)</a>:</h4>
<p>I was just doing premature optimizations. It would indeed be easier to just append them and not do any sorting, so we may just start out like this until we have a significant number of things marked</p>



<a name="228767919"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Filter%20out%20query%20machinery%20from%20compiler%20%E2%80%A6%20compiler-team%23410/near/228767919" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> oli <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html#228767919">(Mar 04 2021 at 13:04)</a>:</h4>
<p>I'll adjust the MCP accordingly</p>



<a name="228772751"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Filter%20out%20query%20machinery%20from%20compiler%20%E2%80%A6%20compiler-team%23410/near/228772751" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html#228772751">(Mar 04 2021 at 13:37)</a>:</h4>
<p><span class="user-mention" data-user-id="124288">@oli</span> I think the reproducible builds argument is worthwhile, FWIW</p>



<a name="228772997"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Filter%20out%20query%20machinery%20from%20compiler%20%E2%80%A6%20compiler-team%23410/near/228772997" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html#228772997">(Mar 04 2021 at 13:39)</a>:</h4>
<p>I also want to note that symbol names might not be the best thing - those aren't necessarily available at runtime and are relatively expensive to resolve, maybe we can just store the ip addresses? (i.e. function pointers without the type signature basically)</p>



<a name="228776871"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Filter%20out%20query%20machinery%20from%20compiler%20%E2%80%A6%20compiler-team%23410/near/228776871" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> oli <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html#228776871">(Mar 04 2021 at 14:03)</a>:</h4>
<p>hmm... I think I know how to implement that, but it may not actually work in practice if a function is duplicated, as it has multiple addresses then</p>



<a name="228776896"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Filter%20out%20query%20machinery%20from%20compiler%20%E2%80%A6%20compiler-team%23410/near/228776896" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> oli <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html#228776896">(Mar 04 2021 at 14:03)</a>:</h4>
<p>we can start with that and see how it goes</p>



<a name="228777127"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Filter%20out%20query%20machinery%20from%20compiler%20%E2%80%A6%20compiler-team%23410/near/228777127" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html#228777127">(Mar 04 2021 at 14:05)</a>:</h4>
<p>Hm, yes</p>



<a name="228777214"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Filter%20out%20query%20machinery%20from%20compiler%20%E2%80%A6%20compiler-team%23410/near/228777214" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html#228777214">(Mar 04 2021 at 14:05)</a>:</h4>
<p>But surely the symbol name is then also not going to work? Unless it's the post demangling symbol... Maybe?</p>



<a name="228777586"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Filter%20out%20query%20machinery%20from%20compiler%20%E2%80%A6%20compiler-team%23410/near/228777586" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> oli <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html#228777586">(Mar 04 2021 at 14:08)</a>:</h4>
<p>idk, I like the pointer idea and will start with that and see how it fares</p>



<a name="228787324"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Filter%20out%20query%20machinery%20from%20compiler%20%E2%80%A6%20compiler-team%23410/near/228787324" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html#228787324">(Mar 04 2021 at 15:04)</a>:</h4>
<p><span class="user-mention" data-user-id="124288">@oli</span> anyway happy to second, not sure if you wanted Felix to take a look specifically</p>



<a name="228787345"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Filter%20out%20query%20machinery%20from%20compiler%20%E2%80%A6%20compiler-team%23410/near/228787345" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> simulacrum <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html#228787345">(Mar 04 2021 at 15:04)</a>:</h4>
<p>I can likely also review impl, though depends on how involved with metadata it gets</p>



<a name="228787465"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Filter%20out%20query%20machinery%20from%20compiler%20%E2%80%A6%20compiler-team%23410/near/228787465" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> oli <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html#228787465">(Mar 04 2021 at 15:05)</a>:</h4>
<p>I talked about this with felix, not the impl, just the idea. So it's not blocked on them</p>



<a name="228788078"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Filter%20out%20query%20machinery%20from%20compiler%20%E2%80%A6%20compiler-team%23410/near/228788078" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> triagebot <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html#228788078">(Mar 04 2021 at 15:08)</a>:</h4>
<p><span class="user-group-mention" data-user-group-id="492">@T-compiler</span>: Proposal <a href="https://github.com/rust-lang/compiler-team/issues/410#issuecomment-790686340">#410</a> has been seconded, and will be approved in 10 days if no objections are raised.</p>



<a name="228935071"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Filter%20out%20query%20machinery%20from%20compiler%20%E2%80%A6%20compiler-team%23410/near/228935071" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Notification Bot <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html#228935071">(Mar 05 2021 at 11:06)</a>:</h4>
<p>This topic was moved by <span class="user-mention silent" data-user-id="124288">oli</span> to <a class="stream-topic" data-stream-id="146212" href="/#narrow/stream/146212-t-compiler.2Fconst-eval/topic/aggregate.20arbitrary.20constants.20at.20compile-time.20into.20a.20sing.2E.2E.2E">#t-compiler/const-eval &gt; aggregate arbitrary constants at compile-time into a sing...</a></p>



<a name="231877820"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/233931-t-compiler/major%20changes/topic/Filter%20out%20query%20machinery%20from%20compiler%20%E2%80%A6%20compiler-team%23410/near/231877820" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> triagebot <a href="https://rust-lang.github.io/zulip_archive/stream/233931-t-compiler/major-changes/topic/Filter.20out.20query.20machinery.20from.20compiler.20.E2.80.A6.20compiler-team.23410.html#231877820">(Mar 25 2021 at 21:19)</a>:</h4>
<p>This proposal has been accepted: <a href="https://github.com/rust-lang/compiler-team/issues/410">#410</a>.</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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